Electrical power plants known as peaker plants are typically built to support peak loads, which generally occur in the afternoon. This is especially so during the summer months when the air conditioning load is high. Electricity during peak times is generated and/or provided at a higher cost as compared to electricity generated generally by base load power plants during off-peak times.
Peak load control is one approach for reducing the amount of electricity generated during peak times. With peak load control, consumers modify their level and pattern of electricity consumption to shed their peak electricity usage or to shift their usage from peak times to off-peak times.
Advanced metering infrastructure (AMI) systems measure, collect and analyze utility usage through a network. Information is distributed to customers, suppliers, utility companies and service providers. This enables power companies to provide demand response products and services to its customers. For instance, customers may alter energy usage patterns from normal consumption patterns in response to demand pricing. This improves system load and reliability.
AMI is configured as a wireless mesh network that routes data between wireless meter reading nodes and the utility company's data center, which ultimately passes the consumption data to a customer billing system at a remote station. Additionally, pricing data and other information is passed from the utility to the consumer. Example wireless meter reading nodes are provided by SkyPilot™ Networks and by Landis+Gyr™.
An advantage of a wireless mesh network is that continuous connections and reconfigurations around broken or blocked paths may be provided by retransmitting messages from a wireless meter reading node to another wireless meter reading node until a destination is reached. A mesh network differs from other networks in that wireless meter reading nodes can all connect to each other via multiple hops. Thus, mesh networks are self-healing and remain operational when wireless meter reading nodes or connections fail.
Current systems utilize mesh protocols that are general purpose and well established. These general purpose mesh protocols are intended to support mobile nodes.
An example mesh protocol is the ad hoc on-demand distance vector (AODV) routing protocol. AODV is a reactive routing protocol, meaning that it establishes a route to a destination only on demand. AODV involves next-hop route table management to be maintained at each node. Route discovery in AODV involves packet flooding. Route table information is kept even for short-lived routes, such as those created to temporarily store reverse paths toward nodes originating route requests.
Another example of a mesh protocol is the optimized link state routing (OLSR) protocol. OLSR is a proactive link-state routing protocol which uses hello and topology control messages to discover and then disseminate link state information throughout the network. The routes to all destinations within the network are known before use and are maintained with routing tables and periodic route management messaging. Since link-state routing requires the topology database to be synchronized across the network, OLSR floods topology data often enough to make sure that the database does not remain unsynchronized for extended periods of time.
Yet another example mesh protocol is the dynamic source routing (DSR) protocol. This protocol uses a reactive approach which also utilizes packet flooding. A route is established only when it is required. The ultimate route that is determined in DSR is a source route, as opposed to AODV's next-hop troute.
One approach for a mesh protocol with stationary nodes, such as electricity meter reading nodes, is disclosed in U.S. Pat. No. 7,035,207. An ad-hoc network comprises a plurality of nodes, where each node has a unique ID and stores a table of nodes. When a node is added to the network, it detects the presence of adjacent nodes. The new node obtains the table stored in each adjacent node and uses that information to update its own table, thereby obtaining information for communicating with every other node in the network. Each of the adjacent nodes obtain information related to communicating with the new node, adjusts its own table of nodes accordingly, and sends update information to nodes adjacent to it to propagate knowledge of the new node.
An ad-hoc network applicable to automatic meter reading (AMR) is disclosed in U.S. published patent application no. 2009/0146838. The network includes stationary meter units coupled to utility meters, mobile relays and a central station. Data from the utility meters are propagated to the central station. Data hops from meter to meter, assisted by mobile relays, and ultimately arrive at the central station. Communication between low power meter units is effective over short distances, while mobile relays bridge over long gaps between the meters and the central station.